Component assembly consisting of a fastener element and a sheet metal part and also a method for manufacturing such a component assembly

ABSTRACT

A component assembly comprises a sheet metal and a fastener element. A flange has a larger diameter and a shaft of smaller diameter extends away from the flange and merges at its end remote from the flange into a cylindrical rivet section. The fastener element is used with sheet metals with thicknesses in the range of 3 mm and larger. With thin sheet metal parts the sheet metal has a smooth pierced cylindrical opening with a diameter corresponding to the diameter of the shaft. The cylindrical rivet section is reshaped to a rivet bead contacting the sheet metal underside. Medium thickness sheet metal parts have a stepped hole with the hole region of larger diameter receiving the rivet bead. For thick sheet metal parts the sheet metal has a conical pierced hole and the cylindrical rivet section is reshaped to a conical rivet bead wedged in the conically diverging hole.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.12/581,800 filed Oct. 19, 2009, which claims priority of German patentapplication No. 10 2008 052 383.6 filed Oct. 20, 2008, and thedisclosures of which are incorporated herein by reference in theirentireties.

FIELD OF THE INVENTION

The present invention relates to a component assembly consisting of afastener element and a sheet metal part as well as a method for themanufacture of such a component assembly. It is everyday practice in themanufacture of motorcar bodies to operate with fastener elements whichare present in the form of rivet elements, piercing and rivetingelements or press-in elements.

BACKGROUND OF THE INVENTION

With a rivet element, the element is inserted into a pre-pierced sheetmetal part and riveted to the sheet metal part by beading over the rivetsection of the fastener element. The fastener element itself has afastener part, i.e. either an internal thread or a bolt shaft with anexternal thread, whereby a further component can be secured to the sheetmetal part using a bolt or a nut respectively. Piercing and rivetingelements are made self-piercing, i.e. the element itself cuts the holein the sheet metal part and is subsequently riveted to the sheet metalpart. With press-in elements the sheet metal part is again alsopre-pierced and the element is then passed through the hole and pressedtogether with the sheet metal part so that sheet metal material flowsinto undercuts of the pressing element and locks the pressing elementrelative to the sheet metal part, so that it is firmly secured to thesheet metal part and cannot be straightforwardly pressed out of thesheet metal part.

Such fastener elements have, in the construction of motorcars, largelydisplaced welding elements which were previously welded to sheet metalbody parts or the like. The welding on of elements is, on the one hand,difficult to integrate into the manufacture of individual components bymechanical deformation and also leads to an undesired contamination ofthe sheet metal part. Further, welding elements cannot be used withvarious sheet metal parts, for example when these are pre-painted orconsist of two sheet metal layers, optionally with a plastic membranedisposed between them. They can also not be used when the sheet metalpart is a high strength part, since the heat which is associating withthe welding operation leads to an unacceptable reduction of the sheetmetal properties in the region of the weld location. In the manufactureof sheet metal parts for motorcars large numbers of parts are requiredand the sheet metal thicknesses in question normally lie in the rangefrom 0.6 mm to 2.5 mm sometimes beyond this to 3 mm or slightly more.

A fastener element in the form of a nut element is known from U.S. Pat.No. 5,251,370 which has a flange part of larger diameter and a shaftpart of smaller diameter which extends away from the flange part andmerges at its end remote from the flange part into a cylindrical rivetsection the outer side of which lies approximately flush with the outerside of the shaft part, i.e. has the same diameter, with the side of theflange part adjacent the shaft part forming a sheet metal contactshoulder and with features providing security against rotation beingprovided at the shaft part and/or in the region of the sheet metalcontact shoulder.

A fastener element of this kind is attached to the sheet metal part inaccordance with the named US patent by means of the so-called clampinghole riveting process. For this purpose, the sheet metal part ispre-pierced and the region around the piercing is shaped into a conicalprojection or into a conical collar. During the passing of the rivetsection of the element through the sheet metal part, which takes placefrom the side of the conical projection, the rivet section is beadedover and dilated and simultaneously the conical projection is at leastpartly reversed, whereby the hole of the conical projection is reducedin diameter. A type of strangle-hold takes place between the sheet metalpart and the fastener element and serves for excellent mechanicalproperties of the connection between the fastener element and the sheetmetal part. The conical projection of the sheet metal parts is madedifferently for different sheet metal thicknesses so that one can coverdifferent sheet metal thicknesses with one element.

In the patent specification it is brought out that the element can beused with sheet metal thicknesses up to 4 mm and, as stated above, sheetmetal thicknesses of greater than 3 mm are relatively rare in motorcarconstruction.

Rivet elements are also used in the manufacture of trucks, however on amuch smaller scale. Essentially only the use of rivet elements frommotorcar manufacture is known, which are also used in thin sheet metalparts of trucks, for example in the region of the driver's cabin. Morestable sheet metal parts of trucks, i.e. with the sheet metalthicknesses greater than 3 mm and normally greater than 4 mm and largerare—if at all—only provided with rivet elements in the most rare cases,since the rivet elements that are available are not designed for suchthick sheet metal parts. Furthermore, far fewer trucks are manufacturedin comparison to motorcars. The methods used in truck manufacture leadto welding elements dominating there.

SUMMARY OF THE INVENTION

The object of the present invention is to propose a component assemblyconsisting of a rivet element and a sheet metal part, and also a methodfor manufacturing such a component assembly, which represents acost-favourable solution even with low quantities and which can be usedeconomically.

In order to satisfy this object, a component assembly of the initiallynamed kind is proposed in accordance with the invention, which ischaracterized in that the fastener element is designed for use withsheet metal parts having thicknesses in the range of 3 mm and larger andin that the sheet metal part lies in one plane, at least in the regionof attachment of the fastener element prior to an after attachment ofthe fastener element and

a) for relatively thin sheet metal parts, the sheet metal part has asmooth, pierced cylindrical opening which has a diameter whichcorresponds at least substantially to the diameter of the shaft part,with the cylindrical rivet section being reshaped to a rivet bead whichcontacts the side of the sheet metal part remote from the sheet metalcontact shoulder, orb) for sheet metal parts of medium thickness the sheet metal part has astepped hole with a cylindrical hole part adjacent to the sheet metalcontact shoulder and a smaller diameter which corresponds at leastsubstantially to the diameter of the shaft part and with a hole regionof a larger diameter which receives the rivet section which has beenbeaded over to form a rivet bead, orc) for relatively thick sheet metal parts in which the sheet metal parthas a thickness which corresponds at least substantially to the totallength of the shaft part and the rivet section, or is thicker, the sheetmetal part is provided with a conical hole which diverges in thedirection from the side of the sheet metal part confronting the sheetmetal contact shoulder to the side remote from the sheet metal contactshoulder, with the cylindrical rivet section being reshaped to a conicalrivet bead which is wedged in the conically diverging hole.

Thus a fastener element is proposed which admissibly has a basic shapewhich is known per se but which can also be used with sheet metal partsthicker than 3 mm when the sheet metal part is appropriately prepared.

It is initially important that the sheet metal part lies in one plane inthe region of attachment of the fastener element both before and alsoafter the attachment of the fastener element, i.e. the sheet metal partis not provided with a conical projection as in clamping hole riveting,but rather the sheet metal part remains in one plane both during thepre-piercing and also during the attachment of the element.

This admittedly does not preclude the sheet metal being re-shaped beforeor after the piercing operation to a boss, with the fastener elementbeing attached to the planar base region of the boss, but rathersignifies that the sheet metal part lies in one plane both in theimmediate vicinity of the attachment of the fastener element and also inradial directions adjacent to the point of attachment.

With relatively thin sheet metal parts, which can for example have athickness between the 3 mm and 4.5 mm, the rivet section which projectsout of the side of the sheet metal part remote from the sheet metalcontact shoulder is beaded over to a rivet bead, with the rivet beadthen so to say contacting the underside of the sheet metal when thesheet metal contact shoulder of the flange part contacts the top side ofthe sheet metal. In order to achieve a planar screwed joint then oneeither has to use a washer with a hole which receives the rivet bead orto operate with a broadened bore in the component to be screwed on toform the joint.

The thread diameter of the fastener element is not restricted to anyparticular sizes, although in truck construction, with thicker sheetmetal parts, bolts are rarely used which have a thread smaller than M8,with thread sizes of M20 and larger not being a rarity.

For somewhat thicker sheet metal parts, for example in the range frombetween 4.5 mm and 6.5 mm, a stepped hole in the sheet metal part isused in accordance with the invention, with the rivet bead beingreceived in the hole region of larger diameter, i.e. not projecting outof the underside of the sheet metal part. This makes the use of aspecial washer or the provision of a special recess in the component tobe screwed on superfluous.

For thick sheet metal parts, for example having a thickness greater than6.5 mm, a hole in the sheet metal part is preferably produced by apiercing process, with the hole being made conically divergent in thedirection going from the side of the sheet metal part which is adjacentto the sheet metal contact shoulder to the remote side of the sheetmetal part. The rivet section is then not shaped into a beaded overrivet bead but rather to a conical shape so that the rivet section iswedged in the conically diverging hole and in this manner prevents thefastener element being pressed out of the sheet metal part.

The fastener element is normally formed as a nut element, i.e. both theflange part and also the shaft part of hollow shape are made hollow witha hollow space having an internal thread. The thread however does notextend into the rivet section because it would otherwise be deformed onbeading over of the rivet section. Instead the rivet section normallymerges via a ring shoulder and a run-in cone into the hollow shaft part,i.e. into the thread. The provision of such a ring shoulder makes itpossible, on the one hand, to keep the rivet section to a suitabledimension in radial thickness and to keep it readily deformable. Theshaft part must however be made adequately thick so that the fastenerelement has a considerable stability and thus suits use in a truck.

This embodiment is particularly favourable because a conically diverginghole of this kind can be made in accordance with the inventionrelatively easily by a technical pressing operation, and indeed over aconsiderable range of sheet metal thicknesses, with the conical rivetbead taking place at a point of the hole corresponding to the totallength of the shaft part with the rivet section. It is simply necessaryto select a die button suitable for the respective sheet metal thicknessin order to achieve the dilation of the rivet section to the conicalshape.

In the attachment of the fastener element to the respective sheet metalpart any noses providing security against rotation that are provided atthe fastener element are pressed into the sheet metal part and thereform corresponding recesses which, in conjunction with the nosesproviding security against rotation, generate the required securityagainst rotation.

The noses providing security against rotation extend preferably in theaxial direction of the shaft part along the latter and/or they extend inradial directions at the sheet metal contact shoulder.

At this point it should be brought out that it is not essential todesign the element such that thinner sheet metal parts lie in the rangebetween 3 to 4.5 mm, that sheet metal parts of medium thickness haverange from 4.5 to 6.5 mm and thicker sheet metal parts have a thicknesslarger than 6.5 mm.

The statement that, with thinner sheet metal parts having a thickness inthe range from 3 to 4.5 mm, the rivet bead is located at the undersideof the sheet metal part signifies that the shaft part of the element isso designed that it has a length of about 3 mm whereas the rivet sectionlikewise an axial length of about 2.5 mm. Since the total length of thethread is determined by the axial height of the flange part and theaxial length of the shaft part, the height of a flange part could beincreased and the length of the shaft part could be reduced, whereby therivet bead at the underside of the sheet metal part will then bepossible with even thinner sheet metal parts, with the result that sheetmetal parts of medium thickness will then start at lower thicknesses,for example now at 4 mm, because a stepped hole can also be reduced withthis sheet metal thickness in which the hole region of larger diameterof larger diameter is also suitable to receive the beaded over rivetsection. Thus, as explained above, a planar screwed joint surfaceresults together with the advantages which proceed therefrom. It wouldhowever also signify that one could then prepare a conically diverginghole for sheet metal parts for thickness of for example 5.5 mm, so thatthe stepped hole, which is more complicated to manufacture would not benecessary at all.

From the above explanations it can be seen that one does not have to useall three possibilities in accordance with the invention and that, inparticular, with a bore with a conically diverging hole, specialadvantages result, particularly since a conical shape of this kind canbe relatively easily manufactured.

The flange part of the fastener element is of round-circular shape inradial cross-section. The element can thus be advantageouslymanufactured by cold deformation from round bar material. Through themanufacture from round bar material the flange part can have a roundedshape in side view which on the one hand ensures adequate strength ofthe flange part to cold deformation and on the other hand an adequateradial extent of the sheet metal contact shoulder, so that the surfacecontact pressure can be kept small. The avoidance of sharp edges, whichdo not arise with the rounded shape is of advantage.

One can thus distinguish three different kinds of attachment of thefastener element for the manufacture of the component assembly. With athinner sheet metal part this is pierced with a hole punch in order toform a smooth pierced cylindrical opening which has a diameter whichcorresponds at least substantially to the diameter of the shaft part,with the shaft part of the fastener element then being pressed throughthe cylindrical hole until the sheet metal contact shoulder of theflange part contacts the sheet metal part at one side and the featuresor noses providing security against rotation have dug into the sheetmetal part and the cylindrical rivet section is re-shaped by means of asuitable die button to form a rivet bead which contacts the side of thesheet metal part remote from the sheet metal contact shoulder.

With a sheet metal part of medium thickness the method is carried out insuch a way that a stepped hole is produced in the sheet metal part witha cylindrical hole region of smaller diameter adjacent to the sheetmetal contact shoulder which corresponds at least substantially to thediameter of the shaft part and with a hole region of larger diameter,with the shaft part of the fastener element being pressed through thehole until the sheet metal contact shoulder of the sheet metal partcontacts one side of the sheet metal part and the features and nosesproviding security against rotation have dug into the sheet metal part,and the cylindrical rivet section is then re-shaped by means of asuitable die button to form a rivet bead, which is received in the holeregion of the large diameter.

The stepped hole is for example manufactured by a drilling procedure orby a two-step pressing process.

With a relatively thick sheet metal part the sheet metal part is piercedwith a hole punch or otherwise in order to form a conical hole whichdiverges in the direction from the side of the sheet metal part adjacentto the sheet metal contact shoulder to the side remote from it, with thehole having a diameter at the side adjacent to the sheet metal contactshoulder which corresponds at least substantially to the diameter of theshaft part, with the shaft part of the fastener element being pressedthrough the hole until the sheet metal contact shoulder of the flangepart contacts one side of the sheet metal part and the features or nosesproviding security against rotation have dug into the sheet metal partand the cylindrical rivet section is then re-shaped by a suitable diebutton into a conical rivet bead which is wedged in the conicallydiverging hole.

It is particularly favourable when the conically extending hole adjoinsa cylindrical region of the hole which is formed adjacent to the sheetmetal contact shoulder. The cylindrical region, which has at leastsubstantially the same diameter as the shaft part, serves on the onehand for a clean guidance of the shaft part of the fastener element andon the other hand that the largest possible security against rotation isproduced in this region, because the noses providing security againstrotation then produce corresponding grooves in the wall of the hole overtheir entire radial depth.

The conical piercing preferably takes place using a hole punch with adiameter corresponding to the diameter of the shaft part in combinationwith a die button of larger diameter. A design of this kind then leadsto the hole punch cutting a hole with a smooth wall in the startingregion of the hole and subsequently a conical piercing slug from theremaining thickness of the sheet metal part, with the maximum diameterof the piercing slug being determined by the diameter of the hole of thedie button. The conicity of the pierced slug is determined by the sheetmetal thickness, the diameter of the hole punch and the diameter of thehole of the die button.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be explained in more detail with reference toembodiments and to the drawings in which are shown:

FIGS. 1A to 1C a fastener element which can be combined in accordancewith the invention with a sheet metal part to form a component assemblyand indeed in a side view onto the rivet section in FIG. 1A, in a partlyaxially sectioned side view in accordance with FIG. 1B and in aperspective representation in accordance with FIG. 1C,

FIGS. 2A to 2C a series of drawings to show the attachment of thefastener element in a thin sheet metal part,

FIGS. 3A to 3C a series of sketches to show the attachment of thefastener element in accordance with FIGS. 1A to 1C to a sheet metal partof medium thickness,

FIGS. 4A to 4D a series of drawings to show the attachment of thefastener element in accordance with FIGS. 1A to 1C to a sheet metal partof medium thickness or greater thickness,

FIGS. 5A to 5D in principle the same situation as in FIG. 3 butincluding the die button used for this purpose and for the thread sizesM8 (FIG. 5A), M10 (FIG. 5B), M12 (FIG. 5C), M14 (FIG. 5D),

FIGS. 6A to 6D in principle the same situation as in FIG. 4 butincluding the die button used for this purpose and for the thread sizesM8 (FIG. 6A), M10 (FIG. 6B), M12 (FIG. 6C), M14 (FIG. 6D),

FIGS. 7A to 7D a series of drawings corresponding to FIGS. 6A to 6D butfor the attachment of the fastener element according to FIGS. 1A to 1Cto a thicker sheet metal part with the die buttons used for this purposeand for the thread sizes M8 (FIG. 7A), M10 (FIG. 7B), M12 (FIG. 7C), M14(FIG. 7D).

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A to 1C first show a fastener element 10 which has a flange part12 of larger diameter D1 and a shaft part 14 of smaller diameter D2which extends away from the flange part 12 and merges at its end remotefrom the flange part 12 into a cylindrical rivet section 18 the outerside 20 of which lies at least substantially flush with the outer sideof the shaft part 14, i.e. has the same diameter D2. The side of theflange part adjacent to the shaft part 14 forms a sheet metal contactshoulder 22 and features providing security against rotation 24 areprovided on the shaft part 14. The features providing security againstrotation could also be provided on a sheet metal contact shoulder (notshown) or both on a sheet metal contact shoulder 22 and also on theshaft part 14, for example with a rectangular shape or with a triangularshape in side view.

The fastener element 10 is designed for use with sheet metal parts withthicknesses in the range from 3 mm and larger.

The attachment of a relatively thin sheet metal part will now bedescribed with reference to the FIGS. 2A to 2C. As shown in FIGS. 2A and2B the sheet metal part 25 lies, at least in the region 26 of attachmentof the fastener element, in one plan both before and after attachment ofthe fastener element.

The fastener element shown here is a nut element with an internal thread28. The fastener element could optionally also be designed as a boltelement. In this case the shaft part 14 would be extended with athreaded part and a cylindrical rivet section will then be designed in amanner known per se as a skirt, similar for example to that shown in theinitially named U.S. Pat. No. 5,251,370 in FIG. 8.

The features 24 providing security against rotation, which are formed bynoses providing security against rotation, form corresponding recessesin the sheet metal part on attachment of the fastener element (as shownin FIG. 2C). Here the noses 24 providing security against rotationextend in the axial direction of the shaft along the shaft part. Theycould, instead of this, or additionally, extend in radial directions atthe sheet metal contact shoulder 22 (not shown).

The sheet metal part in the embodiment in accordance with FIGS. 2A to 2Ccounts as a thinner sheet metal part and has a thickness in the rangefrom 3 to 4.5 mm.

It is furthermore evident from FIGS. 1A to 1C and 2A to 2C that theflange part is circularly round in radial cross-section and in plan viewand in that the flange part has a rounded shape in side view.

Furthermore, it is evident that the fastener element 10 has a hollowshaft part 14 and that the central thread 28 extends through the flangepart 12 and the shaft part 14 and merges via a conical thread run-in 34and a radial shoulder 36 into the rivet section 18.

The component assembly in accordance with FIGS. 2B and 2C with a thinnersheet metal part 25 is produced in that the sheet metal part is piercedwith a hole punch and a die button in order to form a smooth piercedcylindrical opening 40 which has a diameter D2 which corresponds atleast substantially to the diameter of the shaft part 14. For thispurpose the sheet metal part 25 is inserted into a press between a diebutton in the lower tool of the press and a punch in the upper tool ofthe press or in an intermediate platten of the press, with the diebutton having an opening with a diameter which is only fractionallylarger than the diameter of the punch which corresponds to the diameterD2. During the closing of the press the punch is driven through thesheet metal part and a piercing slug arise which is pressed through theopening of the die button and disposed off. Since the opening of the diebutton corresponds at least substantially to the outer diameter of thepunch and is only fractionally larger than this, a cylindrical hole 40with smooth walls arises in the sheet metal part.

It should be pointed out that it will also be possible to attach the diebutton to the intermediate platten of the press and the punch in theupper tool of the press, or to attach the punch to the lower tool of thepress and the die button above the punch to the upper tool of the pressor to the intermediate platten of the press. The punch could also beattached to the intermediate platten of the press and the die button tothe upper tool of the press. Furthermore, the possibility exists ofinstalling the die button and the punch in a so-called C-frame and toeffect the piercing of the sheet metal part by corresponding hydraulicloading of the one or other part, i.e. the die button or the punch.

The shaft part 14 of the fastener element 10 is pressed through thecylindrical hole 40 until the sheet metal contact shoulder 22 of theflange part 12 contacts the one side 42 of the sheet metal part and thefeatures or noses 24 providing security against rotation have dug intothe sheet metal part. The cylindrical rivet section 18 is re-shaped bymeans of a suitable die button (not shown) to a rivet bead 44 whichcontacts the side 46 of the sheet metal part remote from the sheet metalcontact shoulder 22.

The attachment of the fastener element of the sheet metal part normallyalso takes place in a press. For this purpose the fastener element 12 isnormally received in a setting head and a rivet die is positionedbeneath the sheet metal part and has an end face having a shapecomplementary to the rivet bead 44 at the underside of the sheet metalpart. The die button can for example have a ring groove in the end facewhich resembles a semi-circle in radial cross-section, as does also therivet bead 44. I.e. the semi-circular ring groove in the end face of thedie button surrounds a projection which in the region 46 fits radiallyinside the rivet bead 44 and abuts the ring shoulder 36. Outside of thering groove there is a planar surface which enters into contact with theunderside 46 of the sheet metal part 25. By closing of the press thefastener element is so moved from a position above the sheet metal part25 so that the shaft part 14 of the fastener element moves through thehole 40 until the rivet section 18 engages with the ring groove of thenot shown die button and the rivet bead is correspondingly shaped. Thepress also delivers the force necessary in order to press the noses 24providing security against rotation through the sidewall of the hole,whereby corresponding grooves extending in the axial direction areformed in the cylindrical sidewall of the hole 40 by the noses providingsecurity against rotation 24.

Here also the die button can be attached to the lower tool of the pressand the setting head to the upper tool of the press or to anintermediate platten of the press or, in an inverted arrangement, thesetting head can be attached to the lower tool of the press or to theintermediate platten of the press, whereas the die button is mounted onthe intermediate platten of the press or on the upper tool of the pressrespectively. Here the die button or the setting head can also becarried by a corresponding actuating device of a C-shaped frame.

When a press is used the corresponding tools can also be designed asprogressive tools with the piercing being effected in a first stationand the fastener element being inserted in a second station into thepreviously generated hole. The progressive tool can however also havefurther stations so that further working steps can also be carried outat the same time in the press. An arrangement of this kind functionssuch that the sheet metal part is moved continuously through the press,so that for each stroke of the press working processes can besimultaneously carried out on the sheet metal strip in each workingstation of the press. After leaving the press or in the press theindividual sheet metal parts are then separated from one another i.e.from the sheet metal strip.

The manufacture of a component assembly with a sheet metal part ofmedium thickness will now be explained with reference to FIGS. 3A to 3C.The fastener element 10 is here the same fastener element as in theprevious embodiments. The same reference numerals are used for the sameparts and the same features and it will be understood that the previousdescription applies equally for the parts or features with the samereference numerals unless something different is expressed. In thisembodiment a stepped hole 50 is produced in the sheet metal part with acylindrical hole region 52 of smaller diameter D2, which corresponds atleast substantially to the diameter D2 of the shaft part 14, adjacent tothe sheet metal contact shoulder and with a hole part 54 of largerdiameter. The stepped hole 50 can for example be manufactured by adrilling process or by a two-step pressing process.

The manufacture of a stepped hole of the kind shown by means of amilling tool or a specially ground drill is well known per se. Throughmanufacture of such a bore in a two-stepped pressing process the sheetmetal part 25 is first pierced with a hole punch and a die button asdescribed above, with the sheet metal part being pierced somewhat largerthan is required, i.e. with a diameter which is fractionally larger thanD2 or, as described below, is conically pierced so that a divergingconical hole arises. The sheet metal part is then processed in a furtherprocessing station with a second punch at the one side (the lower side46 in FIG. 3) in order to generate with the second punch the hole regionof larger diameter. During this processing metal flows into thepreviously generated hole so that the hole diameter in the hole part ofsmaller diameter is reduced, preferably to a value corresponding to D2.

The shaft part 14 of the fastener element 10 is then pressed through thehole 50 as described for the FIGS. 2A to 2C embodiment until the sheetmetal contact shoulder 22 of the flange part 12 contacts the one side 42of the sheet metal part and the features or noses 24 providing securityagainst rotation have dug into the sheet metal part, as indicated at 30.The cylindrical rivet section 18 is re-shaped to form a rivet bead 44which is received in the hole region 54 of larger diameter. In thisvariant the lower side 46 of the sheet metal forms a planar jointsurface for a further component, i.e. the rivet bead 44 does not projectbelow the lower side 46 of the sheet metal.

A further variant of the method for the manufacture of the componentassembly in accordance with the invention is illustrated graphically inFIGS. 4A to 4D. This method can be used with thicker sheet metal partsor with sheet metal parts of medium thickness, with the use of themethod with a sheet metal part of medium thickness being shown here. Inthis embodiment the sheet metal part is pierced with a hole punch 60 orotherwise in order to form a conical aperture 62 which diverges in thedirection from the side 46 of the sheet metal part 25 adjacent to thesheet metal contact shoulder 22 to the side 44 remote from it, with thehole 42 having a diameter D2 at the side 64 adjacent the sheet metalcontact shoulder 22 which corresponds at least substantially to thediameter D2 of the shaft part 14.

In order to achieve this conically diverging hole 62 a die button 66 isused here which has a circular opening 68 with a diameter greater thanthe diameter D2 of the cylindrical hole punch 60. The central passage 69of the die button below the opening 68 is likewise made conical (orstepped) in order to allow the piercing slug to pass through.

The conicity of the conically diverging region 62 of the hole in thesheet metal part can be selected within the required limits by choice ofa diameter D3 of the opening 68 of the die button in comparison with thediameter D1 of the punch. One preferably endeavours to achieve anincluded cone angel of for example about 7°.

The punch 60 and the die button 66 can, as described in connection withthe embodiment of FIGS. 2A to 2C, be used in a press (alternatively tothis a C-frame can also be used) as likewise described above.

The thicker the sheet metal part the larger must the diameter D3 of theopening 68 be in order to produce a hole with the desired conical shape.

When using a hole punch with a die button of larger diameter the freeend face of the punch first starts to cut a piercing slug out of thesheet metal part. As soon as the cutting forces have exceeded a specificvalue, the material breaks so that a conical piercing slug is pressedout of the sheet metal part. This type of procedure leads to a situationin which the upper region of the hole, as shown at 64, has the shape ofa circular cylinder corresponding to the shape of the punch 60 whereasin the lower region 62 of this embodiment the hole receives the desiredconical shape.

The attachment of the fastener element at the sheet metal part alsotakes place in a press, i.e. in a further station of the same press orin a separate press. The shaft part 14 of the fastener element 10 ispressed through the hole 62 until the sheet metal contact shoulder 22 ofthe flange part 12 contacts the side 42 of the sheet metal part 25 andthe features or noses 24 providing security against rotation have duginto the sheet metal part 25 as indicated at 30. The cylindrical rivetsection 18 is re-shaped by means of a corresponding die button to aconical rivet bead 44 which wedges in the conically diverging hole 62.

Since the rivet section is dilated to form a rivet bead 44 this alsoreceives a diverging conical shape at the outer side 70 which is matchedto the conical shape of the hole 62. One sees that the rivet bead 44here also fully contacts above the lower side 46 of the sheet metalpart, i.e. the side 46 also forms a planar screw joint side here.

It is particularly advantageous in this embodiment that the same type offastening can be used with quite different sheet metal part thicknesseswithout the design of fastener element having to be changed. It issimply necessary to adapt the design of the die button to the respectivethickness of the sheet metal part. The die button must also be matchedto the respective size of the thread of the fastener element, i.e. tothe fastener element itself.

In order to explain this point in more detail the reference is firstmade to FIGS. 6A to 6D which basically show the same subject matter asFIGS. 4B and 4C but together with the respective used die button 80. Onenotes that, in accordance with FIG. 4C, the rivet bead 44 finishes justabove the lower side 46 of the sheet metal part 25. One also sees from acomparison of the drawings of FIGS. 6A, 6B, 6C and 6D that the diebutton respectively has a die button projection 80A, 80B, 80C and 80Dwhich is designed for the beading over, i.e. the dilation anddeformation of the rivet section 18 of the element, with the die buttonprojection 80A being matched to the thread size M8, die buttonprojection SOB to the thread size M10, the projection 80C for the threadsize M12 and the die button 80D to the thread size M14. The invention ishowever in no way restricted to the thread sized but rather can be usedwith all other thread size, i.e. also with elements with thread sizes ofM20 and above.

The FIG. 7 then shows the same method with a thicker sheet metal partwhere the dilated rivet bead 44 now finishes significantly above thelower side 46 of the sheet metal, since the sheet metal part 25 is heresignificantly thicker than the sheet metal part 25 of the FIGS. 6A to6D.

Here also the die buttons for the thread sizes M8, M10, M12 and M14 areshown. One sees that the die button projection 80A, 80B, 80C and 80Dhere admittedly has a similar shape to that of the embodiment of FIGS.6A to 6D but has a larger axial height so that the dilation of the rivetsection of the fastener element 10 can be effected in the desired wayand means.

Finally the FIGS. 5A to 5D show the die buttons which are used for thethread sizes M8, M10, M12 and M14 in order to form the rivet bead 44within the hole region 54 of larger diameter with a stepped hole 50.here the fastener elements are so selected that the shaft part 14 isrelatively short. If the shaft part is made shorter still then thisembodiment can be used with the thinnest sheet metals, i.e. for exampleof 3 mm or fractionally larger to for example 4.5 mm thickness, so thata situation can be avoided in which the rivet bead projects beyond thelower side 45 of the sheet metal part 25. Here also the die buttons areshown for the thread sizes M8, M10, M12 and M14.

It should be pointed out that the designation “thinner sheet metalparts, sheet metal parts of medium thickness and thick sheet metalparts” are relative designations and that the specific dimensions cannotbe prescribed in a fixed form but rather are selected in accordance withthe design of the fastener element. In this connection it is importantthat it is possible for one thread size to cover a wide spectrum ofsheet metal thicknesses with one element, for example from 3 mm to 20 mmor more. In this manner it is possible, despite the if anything smallerquantities which are required for, for example trucks, to neverthelessachieve higher quantities of the elements in total so that these can bemanufactured at favourable price. The storage of the elements is alsosimplified in this manner.

It should be brought out that the features providing security againstrotation described and/or claimed in this application need not beexecuted by raised features but rather could also be executed byrecesses at the fastener element. In this case the fastener element orthe nut element must have a slight oversize relative to the bore. Amixture of raised and recessed features providing security againstrotation could also be considered, for example a sequence of alternatingnoses providing security against rotation and recesses providingsecurity against rotation which are located around the periphery of theshaft part and/or at the sheet metal contact shoulder and preferably—asalso the previously described features providing security againstrotation—are arranged at regular intervals. The total number of thefeatures providing security against rotation is not critical. From 2 to18 and preferably 3 to 12 features providing security against rotationcan be straightforwardly provided around the longitudinal axis of thefastener element, without restriction.

Furthermore it should be mentioned that the field of use of thecomponent assemblies claimed here is not restricted to the manufactureof trucks but rather includes all areas where sheet metal parts withcorresponding thicknesses are used which have to be provided withfastener elements.

In all embodiments all materials can be named as the material forfastener elements which achieve the strength values of class 8 inaccordance with the ISO standard or higher in the context of colddeformation, for example a 35B2 alloy in accordance with DIN 1654. Theso formed fastener elements are suitable, amongst other things, for allcommercial steel materials for deep drawing quality sheet metal partsand also for aluminium or its alloys. Aluminium alloys, in particularthose of higher strength can also be used for the fastener elements, forexample AlMg5. Fastener elements of higher strength magnesium alloyssuch as for example AM50 can also be considered.

The invention claimed is:
 1. A method of manufacturing a componentassembly comprising a fastener element (10) and a sheet metal part (25),wherein the fastener element (10) has a flange part (12) of a largerdiameter (D1) and a shaft part (14) of a smaller diameter (D2) whichextends away from the flange part (12), said shaft part having an end(16) remote from the flange part (12) which merges into a cylindricalrivet section (18), said shaft part having an outer side and saidcylindrical rivet section having an outer side which is at leastsubstantially flush with said outer side of the shaft part (14), i.e.has the same diameter (D2), wherein said flange part (12) has a sideadjacent to the shaft part (14) which forms a sheet metal contactshoulder (22), wherein features providing security against rotation (24)are provided at at least one of the shaft part (14) and the sheet metalcontact shoulder (22), wherein the fastener element is designed for usewith a sheet metal part (25) having a thickness in the range of 3 mm andlarger and the sheet metal part lies in one plane, at least in theregion of attachment of the fastener element prior to and afterattachment of the fastener element, said sheet metal part (25) having athickness which corresponds at least substantially to the total lengthof the shaft part (14) and the rivet section (18) or being thicker, themethod comprising the steps of providing the sheet metal part (25) witha conically diverging hole (62) which diverges in a direction from theside of the sheet metal part confronting the sheet metal contactshoulder (22) to a side (42) remote from the sheet metal contactshoulder (22), inserting the cylindrical rivet section (18) into saidconically diverging hole and reshaping the cylindrical rivet section toa conically diverging rivet bead (44) which is wedged in the conicallydiverging hole (62).
 2. The method in accordance with claim 1 whereinsaid sheet metal part is pierced with a piercing stamp (60) to form saidconically diverging hole (62), with the hole (62) having a diameter (D2)at the side (64) adjacent to the sheet metal contact shoulder (22) whichcorresponds at least substantially to the diameter (D2) of the shaftpart (14).
 3. The method in accordance with claim 1, wherein the shaftpart (14) of the fastener element (10) is pressed through the hole (62)until the sheet metal contact shoulder (22) of the flange part (12)contacts the one side (14) of the sheet metal part (24) and features(24) providing security against rotation have dug into the sheet metalpart (25).
 4. The method in accordance with claim 1, wherein theconically extending hole (62) adjoins a cylindrical region (64) of thehole which is formed adjacent to the sheet metal contact shoulders (22).5. The method in accordance with claim 1, wherein the conicallydiverging hole (62) is produced using a hole punch (60) with a diameter(D2) corresponding to the diameter of the shaft part (14) in combinationwith a piercing die (66) of larger hole diameter (D3).
 6. The method inaccordance with claim 4, wherein the conically diverging hole (62) andthe said cylindrical region is produced using a hole punch (60) with adiameter (D2) corresponding to the diameter of the shaft part (14) incombination with a piercing die (66) of larger hole diameter (D3). 7.The method in accordance with claim 5, wherein the conically diverginghole (62) and the said cylindrical region is produced using a hole punch(60) with a diameter (D2) corresponding to the diameter of the shaftpart (14) in combination with a piercing die (66) of larger holediameter (D3).